overflow.c (4109B)
1 /* 2 * Copyright(c) 2021-2022 Qualcomm Innovation Center, Inc. All Rights Reserved. 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, see <http://www.gnu.org/licenses/>. 16 */ 17 18 #include <stdlib.h> 19 #include <stdio.h> 20 #include <unistd.h> 21 #include <sys/types.h> 22 #include <fcntl.h> 23 #include <setjmp.h> 24 #include <signal.h> 25 26 27 int err; 28 29 static void __check(const char *filename, int line, int x, int expect) 30 { 31 if (x != expect) { 32 printf("ERROR %s:%d - %d != %d\n", 33 filename, line, x, expect); 34 err++; 35 } 36 } 37 38 #define check(x, expect) __check(__FILE__, __LINE__, (x), (expect)) 39 40 static int satub(int src, int *p, int *ovf_result) 41 { 42 int result; 43 int usr; 44 45 /* 46 * This instruction can set bit 0 (OVF/overflow) in usr 47 * Clear the bit first, then return that bit to the caller 48 * 49 * We also store the src into *p in the same packet, so we 50 * can ensure the overflow doesn't get set when an exception 51 * is generated. 52 */ 53 asm volatile("r2 = usr\n\t" 54 "r2 = clrbit(r2, #0)\n\t" /* clear overflow bit */ 55 "usr = r2\n\t" 56 "{\n\t" 57 " %0 = satub(%2)\n\t" 58 " memw(%3) = %2\n\t" 59 "}\n\t" 60 "%1 = usr\n\t" 61 : "=r"(result), "=r"(usr) 62 : "r"(src), "r"(p) 63 : "r2", "usr", "memory"); 64 *ovf_result = (usr & 1); 65 return result; 66 } 67 68 int read_usr_overflow(void) 69 { 70 int result; 71 asm volatile("%0 = usr\n\t" : "=r"(result)); 72 return result & 1; 73 } 74 75 int get_usr_overflow(int usr) 76 { 77 return usr & 1; 78 } 79 80 int get_usr_fp_invalid(int usr) 81 { 82 return (usr >> 1) & 1; 83 } 84 85 int get_usr_lpcfg(int usr) 86 { 87 return (usr >> 8) & 0x3; 88 } 89 90 jmp_buf jmp_env; 91 int usr_overflow; 92 93 static void sig_segv(int sig, siginfo_t *info, void *puc) 94 { 95 usr_overflow = read_usr_overflow(); 96 longjmp(jmp_env, 1); 97 } 98 99 static void test_packet(void) 100 { 101 int convres; 102 int satres; 103 int usr; 104 105 asm("r2 = usr\n\t" 106 "r2 = clrbit(r2, #0)\n\t" /* clear overflow bit */ 107 "r2 = clrbit(r2, #1)\n\t" /* clear FP invalid bit */ 108 "usr = r2\n\t" 109 "{\n\t" 110 " %0 = convert_sf2uw(%3):chop\n\t" 111 " %1 = satb(%4)\n\t" 112 "}\n\t" 113 "%2 = usr\n\t" 114 : "=r"(convres), "=r"(satres), "=r"(usr) 115 : "r"(0x6a051b86), "r"(0x0410eec0) 116 : "r2", "usr"); 117 118 check(convres, 0xffffffff); 119 check(satres, 0x7f); 120 check(get_usr_overflow(usr), 1); 121 check(get_usr_fp_invalid(usr), 1); 122 123 asm("r2 = usr\n\t" 124 "r2 = clrbit(r2, #0)\n\t" /* clear overflow bit */ 125 "usr = r2\n\t" 126 "%2 = r2\n\t" 127 "p3 = sp3loop0(1f, #1)\n\t" 128 "1:\n\t" 129 "{\n\t" 130 " %0 = satb(%2)\n\t" 131 "}:endloop0\n\t" 132 "%1 = usr\n\t" 133 : "=r"(satres), "=r"(usr) 134 : "r"(0x0410eec0) 135 : "r2", "usr", "p3", "sa0", "lc0"); 136 137 check(satres, 0x7f); 138 check(get_usr_overflow(usr), 1); 139 check(get_usr_lpcfg(usr), 2); 140 } 141 142 int main() 143 { 144 struct sigaction act; 145 int ovf; 146 147 /* SIGSEGV test */ 148 act.sa_sigaction = sig_segv; 149 sigemptyset(&act.sa_mask); 150 act.sa_flags = SA_SIGINFO; 151 sigaction(SIGSEGV, &act, NULL); 152 if (setjmp(jmp_env) == 0) { 153 satub(300, 0, &ovf); 154 } 155 156 act.sa_handler = SIG_DFL; 157 sigemptyset(&act.sa_mask); 158 act.sa_flags = 0; 159 160 check(usr_overflow, 0); 161 162 test_packet(); 163 164 puts(err ? "FAIL" : "PASS"); 165 return err ? EXIT_FAILURE : EXIT_SUCCESS; 166 }